Study On Treatment Of Landfill Leachate By Combined Process Of Partial Nitrification And Anammox And Toxic Effect Of Heavy Metals

Landfill leachate is characterized by large variations in water quality,high concentrations of organic matter,high concentrations of NH₄⁺-N,heavy metal species,and imbalanced nutrient elements.The treatment technology has always been a problem in the environmental field.The short-cut nitrification-anaerobic ammonia oxidation process is expected to become a breakthrough point for the treatment of landfill leachate because it does not require low energy consumption and does not require additional carbon sources.In this study,the actual landfill leachate as the research object,the short-cut nitrification SBR-anaerobic ammonia oxidation ASBR combination process to explore the feasibility of its treatment of landfill leachate,while influent NO₂^--N/NH₄⁺-N influent anaerobic Ammonia denitrification performance.In this study,artificially simulated landfill leachate was studied to study the effects of single Cu^2+,composite Cu²⁺and Cd²⁺,composite Cu²⁺and Ni²⁺,composite Cd²⁺and Ni²⁺,composite Cu²⁺?Cd²⁺and Ni²⁺on anaerobic ammonia oxidation.The main findings are as follows:?1?After the short-cut nitrification SBR and the anaerobic ammonia oxidation ASBR were independently started,the two reactors were combined to use the actual landfill leachate as the influent,and deep nitrogen removal was realized at room temperature without adding the organic carbon source.The total nitrogen removal load of the combined process reached0.325 kg/?m³·d?,and the total nitrogen removal rate was as high as 93%.?2?During the SBR-ASBR combination,the effect of influent NO₂^--N/NH₄⁺-N ratio on the anaerobic ammonia oxidation process was investigated.The test results show that the ratio is too large?>1.6?,the effluent contains high concentrations of NO₂^--N and nitrite inhibition,resulting in inhibition of anammox activity;ratio is too small?<0.9?,effluent contains higher concentrations NH₄⁺-N makes the total nitrogen removal effect of the combined process unsatisfactory.Therefore,the ratio of NO₂^--N/NH₄⁺-N in the inlet water of ASBR should be controlled between 0.9 and 1.6.?3?When the concentration of heavy metals reaches a certain concentration,the activity of ANAMMOX sludge will be inhibited,and a certain proportion of anammox bacteria will be inactivated;after being inhibited,the activity can be restored by running with low nitrogen load.The more types of heavy metals(Cu²⁺,Cd²⁺,and Ni²⁺),the greater the toxicity and the greater the difficulty of recovery.?4?The inhibition process of anaerobic ammonia oxidation by heavy metals is essentially the adsorption of heavy metals by EPS in anammox sludge.When the heavy metal content in EPS reaches a certain amount,the anammox activity is inhibited and a certain amount Anaerobic ammonia oxidation was inactivated.The inhibition of anaerobic ammonia oxidation activity of the active process,in essence,the value of anammox bacteria and heavy metals in the EPS precipitation and decreased to a lower level,anaerobic ammonia oxidation sludge recovery activity.